"/usr/src/linux-2.4.21" is a folder with a brand new kernel that was just unpacked. Nothing in this kernel has been altered, it is untouched.

## Since we have a brand new kernel, we make sure it is ready for us
## and set to a common base state: (only doing this for brand new kernel:)
hoch:/usr/src/linux-2.4.21# make mrproper

## Now we copy a ".config" file from a kernel that we know works
## for this machine:
hoch:/usr/src/linux-2.4.21# cp ../linux-2.4.20/.config ./.config

## Now we can configure this new kernel with "make oldconfig" to have it
## skip options that we know work, and only stop on new or different
## options:
## (New or different options are in BOLD RED with larger font.)